Agree with comments above that option 1 is best and that you’re not going to find a perfect match for either your amps or preamp. With that, I’m just going to dumb this down a bit in an effort to simplify things. This assumes you’re not looking for absolute state-of-the-art surround performance and would be happy with very, very good 5.1 sound that doesn’t compromise your 2-channel performance in any way. Given you’re not going to perfectly match your current electronics anyway, what about buying a very good A/V receiver with a warmish sound? This way you’re at least keeping the general character of your electronics intact, and you’re getting all the amplification and surround processing you need in one relatively cost-effective box that can be easily and economically upgraded as technology inevitably progresses. Here’s an example of an AVR that might fit the bill nicely...
https://www.accessories4less.com/make-a-store/item/marsr8012/marantz-sr8012-11.2-ch-x-140-watts-netw...
While this will not be a perfect solution to your situation, it’s hard to believe this setup wouldn’t produce a highly satisfying and involving 5.1 experience. And there’s no guarantee you’ll get a much better match by going through the time, effort, and considerable expense of finding a suitable separate prepro and multichannel amp. Obviously if you’re after SOTA multichannel performance it’s worth going down that rabbit hole, but if not I think you could be very happy and maybe even pleasantly surprised with the performance of this setup (along with the several extra thousands of dollars you’ll have in your bank account). Just another option to consider FWIW. Best of luck in your quest.
https://www.accessories4less.com/make-a-store/item/marsr8012/marantz-sr8012-11.2-ch-x-140-watts-netw...
While this will not be a perfect solution to your situation, it’s hard to believe this setup wouldn’t produce a highly satisfying and involving 5.1 experience. And there’s no guarantee you’ll get a much better match by going through the time, effort, and considerable expense of finding a suitable separate prepro and multichannel amp. Obviously if you’re after SOTA multichannel performance it’s worth going down that rabbit hole, but if not I think you could be very happy and maybe even pleasantly surprised with the performance of this setup (along with the several extra thousands of dollars you’ll have in your bank account). Just another option to consider FWIW. Best of luck in your quest.
